Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q9/00—Electrically-short antennas having dimensions not more than twice the operating wavelength and consisting of conductive active radiating elements
  • H01Q9/04—Resonant antennas
  • H01Q9/30—Resonant antennas with feed to end of elongated active element, e.g. unipole
  • H01Q9/42—Resonant antennas with feed to end of elongated active element, e.g. unipole with folded element, the folded parts being spaced apart a small fraction of the operating wavelength
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q1/00—Details of, or arrangements associated with, antennas
  • H01Q1/27—Adaptation for use in or on movable bodies
  • H01Q1/34—Adaptation for use in or on ships, submarines, buoys or torpedoes
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q21/00—Antenna arrays or systems
  • H01Q21/06—Arrays of individually energised antenna units similarly polarised and spaced apart
  • H01Q21/20—Arrays of individually energised antenna units similarly polarised and spaced apart the units being spaced along or adjacent to a curvilinear path
  • H01Q21/205—Arrays of individually energised antenna units similarly polarised and spaced apart the units being spaced along or adjacent to a curvilinear path providing an omnidirectional coverage
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q5/00—Arrangements for simultaneous operation of antennas on two or more different wavebands, e.g. dual-band or multi-band arrangements
  • H01Q5/20—Arrangements for simultaneous operation of antennas on two or more different wavebands, e.g. dual-band or multi-band arrangements characterised by the operating wavebands
  • H01Q5/25—Ultra-wideband [UWB] systems, e.g. multiple resonance systems; Pulse systems
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q5/00—Arrangements for simultaneous operation of antennas on two or more different wavebands, e.g. dual-band or multi-band arrangements
  • H01Q5/30—Arrangements for providing operation on different wavebands
  • H01Q5/307—Individual or coupled radiating elements, each element being fed in an unspecified way
  • H01Q5/314—Individual or coupled radiating elements, each element being fed in an unspecified way using frequency dependent circuits or components, e.g. trap circuits or capacitors
  • H01Q5/321—Individual or coupled radiating elements, each element being fed in an unspecified way using frequency dependent circuits or components, e.g. trap circuits or capacitors within a radiating element or between connected radiating elements

Definitions

• the present invention relates to a structural antenna, and in particular a wideband structural antenna for operation in the HF frequency range.
• the invention relates to an antenna system of the type referred to in the preamble of Claim 1.
• the antennae used at present must not only meet the requirement of operating in a plurality of transmission channels throughout the frequency range of the band and allow links in the proximity of the horizon (surface wave or sea wave, for distances up to approximately 100 km) , beyond the horizon (BLOS, Beyond Line of Sight, for distances of more than approximately 100 km) and at high angles of elevation (NVIS, Near Vertical Incidence Skywave) , but must also be as compact as possible in order to be compatible with the available space on board naval units.
• Multichannel systems have therefore been proposed for combining a plurality of transmission channels by using a single wideband antenna at the input of which a multiplicity of transmission channels are added by means of combining circuits .
• These multichannel systems are constructed with the aid of power amplifiers (generally of the order of 1 kW) which can be independently assigned to different services or to a single channel.
• This problem is conventionally resolved by fitting the ship with multiple antennae, having different configurations and operating in separate frequency sub-bands, each being allocated to a specific channel.
• “fan” antennae are used for links with high angles of elevation at frequencies in the range from 2 MHz to 8 MHz, and antennae with "whip" geometry, loaded if necessary, are used for sea wave communications and communications beyond the horizon at frequencies in the range from 10 MHz to 30 MHz.
• the object of the present invention is to provide a wideband multifunction antenna system for operation in the HF frequency range, which is designed particularly for fixed installations on board naval units, and which makes it possible to construct an efficient, flexible and multipurpose multichannel radio communication system in a limited installation space.
• a further object of the invention is to provide an antenna system which can form the base of a more complex antenna system, possibly one which also permits the control of the radiation pattern in terms of directionality and scanning capacity.
• the invention proposes a structural antenna system having the characteristics claimed in Claim 1.
• the antenna system proposed by the present invention is guaranteed to overcome the limits of prior art antennae, as a result of the special arrangement of the radiating elements of the antenna and the inclusion among these of a pre-existing naval structure having a predominantly vertical extension, providing support for the linear radiating arrangement together with intrinsic compensation of the distortion effects of the radiation characteristics of this arrangement due to the presence of the said naval structure.
• the achievement of a multichannel communication mode is dependent on the provision of electrical impedance devices which create a multifunction antenna, in other words one which can be configured according to the operating frequency.
• the provision of electrical impedance devices also advantageously makes it possible to compensate for distortion effects due to coupling with other naval structures present in all cases, thus enabling the loading condition of the antenna to be modified either in the design phase or during installation.
• the structural antenna system proposed by the invention in its simplest configuration, is characterized by the coupling of a linear radiating arrangement (produced by the combination of variously orientated wire elements) to a pre-existing electrically conducting naval structure having a predominantly vertical extension, such as a funnel or turret, whose height is typically comparable with that of a conventional naval "whip" antenna.
• a linear radiating arrangement produced by the combination of variously orientated wire elements
• Such a structure not only has the intrinsic functionality for which it is present in the naval environment, but also acts as a support for the linear radiating arrangement and as part of the antenna system itself.
• the resulting structural antenna system is fairly compact and does not significantly increase the overall dimensions of the pre-existing structure forming part of the naval environment.
• the linear radiating arrangement has a predominantly vertical overall dimension and comprises a fed conducting branch, having a predominantly vertical extension, connected by means of at least one conducting branch with a predominantly horizontal extension to the naval structure acting as a ground return conducting element, in such a way as to form at least one closed path.
• a type of structure including at least one additional angled conducting branch connecting the fed branch having a vertical extension with the connecting branch having a horizontal extension makes it possible to form a plurality of current paths by convenient selection of a configuration of the radiating elements of the antenna.
• the selection of one of the aforesaid configurations is automatic and dependent on the different frequency sub-bands of the HF range, and is carried out as a result of the behaviour of the electrical impedance devices, made at least partially in the form of lumped constant two-terminal circuits, preferably two-terminal LC circuits in series or parallel resonant configurations, which act as bandpass or bandstop filters for the current flowing in the radiating elements of the antenna.
• the electrical impedance devices make it possible to selectively modify the flow of current in the conducting branches at the different frequencies (and thus in accordance with the type of service) in such a way as to form radiation patterns at low, medium and high angles of elevation, while simultaneously acting as a distributed matching circuit along the antenna .
• a structural antenna system based on the radiating arrangement proposed by the invention can be configured with one or more feed points, and can operate in either single- channel or multichannel mode.
• An antenna system comprising a single linear radiating arrangement, and therefore a single feed point, can be used as a multifunction wideband radiator (in the sense defined above) with a standing wave ratio of less than 3:1 throughout the HF band and with a radiation efficiency of approximately 0.5%-30% between 2 MHz and 10 MHz, approximately 30%-50% between 10 MHz and 15 MHz, and approximately 50%-80% between 15 MHz and 30 MHz.
• a multiple feed structural antenna system is produced which is adapted to operate in either multichannel or single- channel mode, with the possibility of shaping and directing the radiation pattern according to the specific type of service .
• the configuration with multiple feed points (ports) makes it possible to allocate a different channel (signal) to each port, thus avoiding the use of combining circuits, and providing the evident advantages of higher efficiency of the antenna system and a lower cost of the transmission systems, while limiting the overall dimensions of the radiating arrangements .
• Another function relates to the possibility of operating the single-channel antenna system as an array antenna with aiming and scanning capabilities, by controlling the amplitudes and phases of the feed signal to each radiating arrangement.
• the proposed configuration is adapted to produce sufficiently uniform radiation in all directions at the low frequencies (2 MHz - 10 MHz) and omnidirectional radiation in the horizontal planes at the medium and high frequencies (10 MHz - 30 MHz) , thus permitting simultaneous provision of all the services required in the HF band, namely sea wave, sky wave and beyond horizon communication at different angles of elevation, without the need for any mechanical modification or reconfiguration of the antenna system or of its feed circuit.
• Figure 1 is a schematic representation, in a side view and from above, of a structural antenna system proposed by the invention
• Figure 2 is a schematic representation of the distribution of electrical impedance devices along the linear radiating arrangement of the antenna system of Figure 1;
• FIG 3 is a schematic representation of a feed circuit for the antenna system of Figure 1;
• Figures 4a-4f are representations of the radiation patterns of the structural antenna system of Figure 1, at different frequencies in the HF band;
• Figure 5 is a schematic representation, in a perspective view, of a structural antenna system with multiple feed proposed by the invention.
• Figure 6 shows a control system for the structural antenna system with multiple feed of Figure 4.
• a wideband multifunction structural antenna system proposed by the invention adapted to o perate in the HF frequency range (2 MHz - 30 MHz), is generally indicated by 10.
• Figure 1 it is shown in an installation configuration for use as a transmitting antenna, connected to a feed unit 12 and to a ground plane GND.
• the antenna system of Figure 1 represents a structural antenna comprising a single linear radiating arrangement 14 (and therefore having a single feed point) , coupled to a preexisting electrically conducting naval structure having a predominantly vertical extension, such as a funnel F, located in a meridian plane.
• the overall configuration of the antenna system is predominantly vertical, and the linear radiating arrangement is preferably mounted on a horizontal ground plane, for example a surface of the naval structure.
• the linear radiating arrangement of the antenna comprises wire radiating elements with a predominantly vertical extension and wire radiating elements with a predominantly transverse extension, all these elements being coplanar.
• the radiating elements with a predominantly vertical extension form a first vertical conducting branch H connected to a terminal of the feed unit 12.
• the naval structure consisting of a funnel F, having a cylindrical or truncated conical body erected on a surface of the naval structure, is made from conducting material or is made conducting by the application of a metallic coating. It forms the return conductor, being electrically connected to the ground plane GND.
• the fed conducting branch H is connected to the funnel structure F by a transverse conducting branch W consisting of at least one radiating element having a predominantly horizontal extension, and forms with these latter a closed rectangular path between the feed unit and the ground plane.
• the transverse conducting branch W is connected to the fed branch H at an intermediate point of the branch, at a predetermined distance from the upper free end of the latter.
• An angled conducting branch A is connected at its upper end to the transverse conducting branch W and at its lower end to the vertical conducting branch H, at corresponding intermediate points of the aforesaid branches, and forms a second closed polygonal path between the feed unit and the ground plane, inside the rectangular path defined by the branches H and W.
• the vertical overall dimension of the linear radiating arrangement (in other words, the height of the conducting branch H) is between approximately 8% and 10% of the maximum wavelength in the HF band (150 metres at the 2 MHz frequency) , and is preferably 12 metres.
• the height of the funnel body is generally between approximately 6% and 10% of the maximum wavelength in the HF band.
• the overall horizontal dimension of the linear radiating arrangement is between approximately 1% and 2% of the maximum wavelength in the HF band (150 metres at the 2 MHz frequency), and is preferably 2 metres.
• the diameter of the body (which is cylindrical in the illustrated embodiment) of the funnel structure is generally between 2% and 5% of the maximum wavelength in the HF band.
• the height of the angle conducting branch A is equal to approximately 2% of the maximum wavelength in the HF band, and is preferably equal to 3 metres, while its transverse extension is equal to approximately 0.7% of the aforesaid wavelength and is preferably equal to 1 metre.
• the diameter of the radiating elements forming the conducting branches is approximately 0.1% of the maximum wavelength in the HF band, and preferably equal to 0.15 metres.
• the naval structure such as the funnel body F is a hollow structure whose lateral wall generally has a thickness of 0.25 metres.
• the transverse conducting branch W is connected to the vertical branch H at an intermediate point of the latter, at a distance of 2 metres from its upper free end.
• the angle conducting branch A is connected to the transverse conducting branch W at its median point, and to the vertical conducting branch H at a height above its median point, and preferably at 7 metres from the ground plane, corresponding to approximately 60% of the total height of the branch.
• electrical impedance devices Zl and Z2 are interposed along the conducting branch H, an impedance device Z3 is interposed along the transverse conducting branch W, and a further impedance device Z4 is interposed along the angled conducting branch A, preferably along the vertical leg.
• each of the impedance devices Zl and Z2 comprises a two-terminal reactive circuit, such as a series resonant LC circuit, while each of the impedance devices Z3 and Z4 comprises a two-terminal resistive circuit such as a simple resistor .
• the electrical parameters of the impedance devices Zl and Z2 are such that they form lumped .filter circuits adapted to selectively impede the propagation of electric current along the conducting branch in which they are connected, in corresponding sub-bands of the HF frequency range.
• the electrical parameters of the impedance devices Z1-Z4, taken together, are such that they form a distributed matching circuit along the linear radiating arrangement of the antenna .
• the impedance devices Zl, Z2 and Z4 are positioned, respectively, at heights of 3.25 metres, 8.25 metres and 7.75 metres above the ground plane GND, while the impedance device Z3 is positioned at 1.25 metres from the lateral wall of the naval tunnel structure F.
• the electrical parameters of inductance and capacitance of the two-terminal series LC circuits forming the impedance devices Zl and Z2 have the following values :
• the two-terminal circuit Zl has an inductive component of 1.12 ⁇ H and a capacitive component of 569.1 pF;
• the two-terminal circuit Z2 has an inductive component of 0.073 ⁇ H and a capacitive component of 59.8 pF.
• the electrical resistance parameter of the two-terminal circuit forming the impedance devices Z3 and Z4 has the following values:
• the dipole Z3 has a resistive component of 48.6 ⁇ ;
• the dipole Z4 has a resistive component of 61 ⁇ .
• the feed unit 12 includes a signal matching and distribution circuit, such as that shown in Figure 3.
• the unit 12 is operatively arranged at the base of the linear radiating arrangement of the antenna and electrically connected between the conducting branch H and a transmission line for carrying a radio frequency signal.
• the feed unit 12 has an input IN coupled to a radio frequency signal source 20 via a transmission line L, such as a coaxial cable, and an output port OUT, into which the vertical conducting branch H of the antenna is fitted with the use of an insulator IS.
• a transmission line L such as a coaxial cable
• the feed unit includes an impedance step-up transformer T having a predetermined impedance transformation ratio n, preferably equal to 3.7, referred to ground, having one terminal connected to the input IN for receiving the radio frequency signal, and the other terminal connected to the output port OUT.
• the feed unit which has been described can be enclosed in a boxlike metal container 30, forming an electrical screen and connected to the ground plane GND. This forms a 50 ohm matching unit for the incoming transmission line.
• the antenna system proposed by the invention acts as described below.
• Figures 4a-4f show the radiation patterns at different frequencies, in the vertical (left-hand pattern) and horizontal (right-hand pattern) planes.
• a radio frequency signal output by the external source 20 and carried along the transmission line L, is applied to the impedance transformer T and is transferred to the output OUT of the feed unit 12, connected to the conducting branch H of the antenna. From this point, it is distributed along the linear radiating arrangement and the funnel structure in a selective way according to the frequency and therefore the type of function required from the antenna, depending upon the configuration of the linear arrangement determined by the behaviour of the impedance devices.
• the impedance device Z2 comes into action to impede the flow of current in the upper portion of the fed branch H, so that the current in the linear arrangement flows through the lower portion of the conducting branch H, the inner path along the angled conducting branch A and the portion of the conducting branch W adjacent to the funnel structure.
• the antenna system thus has a radiation mode similar to that which would be provided by a combination of the radiation of a "half-loop" configuration and the radiation of a "whip" configuration.
• the resulting radiation pattern (the radiation patterns of Figures 4a-4c) is substantially uniform in all directions, thus permitting sea wave and sky wave communications at different angles of elevation.
• a structural antenna system with multiple feed comprising a plurality of linear radiating arrangements 114 having geometries and characteristics similar to those of the arrangement 14 described with respect to the embodiment shown in Figure 1, which relates to a structural antenna system with a single feed.
• Each linear radiating arrangement 114 is connected to a corresponding feed unit 112, similar to the unit 12 described, and is coupled to a pre-existing electrically conducting naval structure, having a predominantly vertical extension, such as a funnel F forming a return conductor electrically connected to a horizontal ground plane GND, for example a surface of the naval structure.
• a pre-existing electrically conducting naval structure having a predominantly vertical extension, such as a funnel F forming a return conductor electrically connected to a horizontal ground plane GND, for example a surface of the naval structure.
• a control and signal processing unit 200 is connected to the feed units 112 and is arranged to control the amplitude and phase of the radio frequency currents injected into the linear radiating arrangements 114 from the signal source through the corresponding feed units 112.
• the currents are distributed along the conducting branches and the cylindrical conducting body of the funnel structure according to the frequency and the amplitudes and phases of the radio frequency signals.
• the six feed points can be fed simultaneously or with a predetermined phase difference, and partially if necessary, thus providing omnidirectional multichannel radiation configurations or directive configurations with scanning capability, by addition of the radiated fields in the air.

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• Details Of Aerials (AREA)
• Variable-Direction Aerials And Aerial Arrays (AREA)
• Input Circuits Of Receivers And Coupling Of Receivers And Audio Equipment (AREA)
• Inorganic Compounds Of Heavy Metals (AREA)

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• 2005
  • 2005-06-15 IT IT000417A patent/ITTO20050417A1/it unknown
• 2006
  • 2006-06-12 PT PT06756115T patent/PT1920498E/pt unknown
  • 2006-06-12 DE DE602006011180T patent/DE602006011180D1/de active Active
  • 2006-06-12 CN CN2006800295459A patent/CN101243579B/zh not_active Expired - Fee Related
  • 2006-06-12 SI SI200630595T patent/SI1920498T1/sl unknown
  • 2006-06-12 US US11/917,756 patent/US7969368B2/en not_active Expired - Fee Related
  • 2006-06-12 EP EP06756115A patent/EP1920498B1/de not_active Not-in-force
  • 2006-06-12 WO PCT/IB2006/051863 patent/WO2006134543A1/en active Application Filing
  • 2006-06-12 AU AU2006257238A patent/AU2006257238B2/en not_active Ceased
  • 2006-06-12 PL PL06756115T patent/PL1920498T3/pl unknown
  • 2006-06-12 ZA ZA200800250A patent/ZA200800250B/xx unknown
  • 2006-06-12 DK DK06756115.9T patent/DK1920498T3/da active
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  • 2006-06-12 AT AT06756115T patent/ATE452436T1/de not_active IP Right Cessation
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